June, 1906.] Key to the Order T/iysanura. 545 



Galium trifidum L. Woods, southeast of Laboratory. 



Juncus tenuis Willd. Edge of Bay near the Cedar Point Dock. 



Lathyrus maritimus (L.) Bigel. This species, between Rye Beach and the 



Black Channel, was collected by R. F. Griggs, 1903, E. L. Moseley, 



1904, and again by the writer, 1905. At Presque Isle, Erie, Pa., this 



species is very abundant. 

 Lemna minor L. Ponds, Ridge Section. 

 Lysimachia nummularia L. Near the lighthouse. 

 Monarda mollis L. The most common Monarda on Cedar Point. 

 Polygonum pennsylvanicum L. Marsh near Laboratory. 

 Potamogeton amplifolius Tuckerm. 

 Potamogeton foliosus Raf. Both the above species east of entrance to 



Biemillers Cove. 

 Potamogeton lucens L. Near the Black Channel. 

 Rumex altissimus Wood. Marsh north of "White House." 

 Sagittaria graminea Mx. Opposite Laboratory at western edge of 



Biemillers Cove and near the "Carrying Ground." 

 Thalictrum polygamum Muhl. Edge of marsh near the Black Channel. 

 Toxicodendron pubescens Mill.- On sand dunes near Laboratory. 



Prof. E. L. Moseley^ in listing the vegetation of the bar between the 

 Black Channel and Rye Beach mentions the following species, none of 

 which were included in the "Flora of Cedar Point": 

 Equisetum prafense Ehrh. 

 Gentiana andrewsii Griseb. 

 Liriodendron tulip ifera L. 

 Muhlenbergia mexicana (L.) Trin. 

 Solidago canadensis L. 



1. Kellerman, W. a. and Jexxixgs, O. E. Flora of Cedar Point. 

 Ohio Nat. 4 ; 186-190. June, 1904. 



2. Greene, E. L. Segregates of Rhus, Leaflets, 1 : 114-144. Nov. 

 24 and Nov. 29, 1905. 



3. Moseley, E. L. Formation of Sandusky Bav and Cedar Point. 

 Proc. Ohio State Acad. Sci., 4 : 179-238. 1906. 



Carnegie Museum, March 28, 1906. 



KEY TO THE FAMILIES AND GENERA OF THE ORDER 



THYSANURA. 



C. F. Jacksox. 



The order Thysanura comprises on the whole, a group of 

 very small insects, the largest of which do not much exceed 

 25 mm. in length. They may be found in almost every con- 

 ceivable locality, under old logs, in moss and grass, along the 

 margin of stagnant pools and even in our dwellings. Yet 

 strange to say since the time of Degeer, Nicolet and Sir John 

 Lubbock but little has been added to our knowledge of Thysa- 

 nura and the study of this most interesting order of insects has 

 till within the last few years been very much neglected. 



As in all other branches of science, much confusion has arisen 

 as to the identity of species. This is due partlt to the fact that 

 the descriptions given by the early writers are frequently so 

 short and incomplete that the species, or even the genus, cannot 



